Driving method for electro-optical apparatus, driving circuit therefor, electro-optical apparatus, and electronic equipment

• US 20020018056A1
• Filed: 07/11/2001
• Published: 02/14/2002
• Est. Priority Date: 07/24/2000
• Status: Active Grant

• Current Assignee: 138 East LCD Advancements Limited (Vector Capital Corporation)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Matsueda, Yojiro, Ishiguro, Hideto, Ozawa, Tokuro
• Granted Patent: US 7,038,645 B2
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G09G 2300/0814 used for selection purposes, e.g. logical AND for partial update
• CPC Class Codes: G09G 2300/0842 forming a memory circuit, e.g. a dynamic memory with one capacitor
• CPC Class Codes: G09G 2310/027 Details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
• CPC Class Codes: G09G 3/2011 by amplitude modulation
• CPC Class Codes: G09G 3/2074 using sub-pixels
• CPC Class Codes: G09G 3/3659 the addressing of the pixel involving the control of two or more scan electrodes or two or more data electrodes, e.g. pixel voltage dependant on signal of two data electrodes
• CPC Class Codes: G09G 3/3677 suitable for active matrices only
• CPC Class Codes: G09G 3/3688 suitable for active matrices only

Abstract

The invention obtains high-quality display by suppressing display unevenness. Sub-pixels are disposed correspondingly to each set of the intersections between 3 m pairs of paired scanning lines, which are formed in such a manner as to extend in the X-direction, and n pairs of paired data lines, which are a digital data line and an analog data line and extend in the Y-direction. Further, a set of sub-pixels consecutively arranged in the Y-direction is driven as one pixel. In this case, in a first mode, each of the sub-pixels of one pixel turns on or off according to gradation data representing the gradation level of this pixel. Further, in a second mode, a voltage signal representing the gradation level of this pixel is applied to the sub-pixels of one pixel. Furthermore, in a first case of the second mode, the voltage signals are supplied by the first data line driving circuit in line sequence. Moreover, in a second case of the second mode, voltage signals are supplied by a second data line driving circuit in point sequence.

Claims

1. A method of driving an electro-optical apparatus, which includes a set of sub-pixels that adjoin one another and that are disposed correspondingly to intersections between scanning lines, which are formed in a direction of a row, and paired data lines, which include first and second data lines formed in a direction of a column, as one pixel, comprising the steps of:

turning each of said sub-pixels of said one pixel on or off in a first predetermined mode according to corresponding bits of gradation data, which designate a gradation level of said pixel and are supplied through a corresponding first data line;

supplying a voltage signal, which corresponds to the gradation level of said pixel, through a corresponding second data line; and

applying the voltage signal in a second predetermined mode in common to said sub-pixels of said one pixel.

2. The method of driving an electro-optical apparatus according to claim 1, further including the steps of holding a corresponding bit of the gradation data with holding devices of said electro-optical apparatus, provided correspondingly to each of said sub-pixels, turning said sub-pixels off once in the first mode regardless of data represented by the corresponding bit held in said holding devices, and thereafter, turning said sub-pixels on or off according to the bits of the gradation data, which are preliminarily held in said holding devices.

3. The method of driving an electro-optical apparatus according to claim 1, further including the steps of selecting said second data lines in a predetermined order in the second mode correspondingly to said sub-pixel corresponding to a selected row, and applying a voltage signal to said selected second data line.

4. The method of driving an electro-optical apparatus according to claim 1, further including the step of simultaneously applying voltage signals through said second data lines to said sub-pixels corresponding to said selected rows in the second mode.

5. A driving circuit for an electro-optical apparatus, adapted to drive a set of sub-pixels that adjoin to one another in a direction of a column and that are disposed correspondingly to intersections between scanning lines, which are formed in a direction of a row, and paired data lines, which include first and second data lines formed in a direction of a column, as one pixel, said driving circuit comprising:

a scanning line driving circuit that outputs, in a first predetermined mode, a scanning signal, which selects said scanning lines line by line, to each of said scanning lines and outputs, in a second predetermined mode, a scanning signal, which selects said scanning lines every lines of the number of said sub-pixels of one pixel, to each of said scanning lines; and

a data line driving circuit that outputs, in the first predetermined mode, a corresponding bit of gradation data representing a gradation level of a pixel including said sub-pixel, which corresponds to the intersection corresponding to said scanning line selected by said scanning line driving circuit, to a corresponding first data line and outputs, in the second mode, a voltage signal corresponding to a gradation level of the pixel to corresponding second data lines that corresponds to the intersection corresponding to the said sub-pixels grouped as one pixel.

6. The driving circuit for an electro-optical apparatus according to claim 5, said data line driving circuit including:

a first driving circuit; and

a second driving circuit, said first driving circuit outputting a bit to said first data line in the first mode, and one of said first driving circuit and said second driving circuit outputting a voltage signal to said second data line.

7. The driving circuit for an electro-optical apparatus according to claim 6, said first driving circuit including:

a first circuit that outputs, in the first mode, a corresponding bit of gradation data of a pixel including one of sub-pixels, which is placed on said selected scanning line to said first data line corresponding to said one of sub-pixels; and

a second circuit that outputs, when said second driving circuit outputs a voltage signal only to said second data line in the second mode, data obtained by performing a digital-to-analog conversion on gradation data of a pixel including one of said sub-pixels, which is placed on said selected scanning line, to said second data line corresponding to said one of said sub-pixels.

8. The driving circuit for an electro-optical apparatus according to claim 6, said second driving circuit being a circuit that samples and outputs, when said first driving circuit outputs a voltage signal only to said second data line in the second mode, voltage signals, whose levels correspond to a gradation level of a pixel including one of said sub-pixels, which is placed on said selected scanning line, in sequence to said second data line corresponding to said one of said sub-pixels.

9. An electro-optical apparatus, adapted to drive a set of sub-pixels that adjoin to one another in a direction of a column and that are disposed correspondingly to intersections between scanning lines, which are formed in a direction of a row, and paired data lines, which include first and second data lines formed in a direction of a column, as one pixel, said apparatus comprising:

a scanning line driving circuit that outputs, in a first predetermined mode, a scanning signal, which selects said scanning lines line by line, to each of said scanning lines and that outputs, in a second predetermined mode, a scanning signal, which selects said scanning lines every lines of the number of said sub-pixels of one pixel, to each of said scanning lines; and

a data line driving circuit that outputs, in the first predetermined mode, a corresponding bit of gradation data representing a gradation level of a pixel including said sub-pixel, which corresponds to the intersection corresponding to said scanning line selected by said scanning line driving circuit, to a corresponding first data line and that outputs, in the second mode, a voltage signal corresponding to a gradation level of the pixel to corresponding second data lines that corresponds to the intersection corresponding to the said sub-pixels grouped as one pixel.

10. The electro-optical apparatus according to claim 9, said sub-pixel including:

a first switch, adapted to turn on or off in the first mode according to a signal supplied to a write control line provided correspondingly to each of said scanning lines;

a holding device that holds, when said first switch turns on in the first mode, data according to a bit supplied to a corresponding one of said first data lines;

a second switch that selects, after a signal, which turning off said sub-pixel, is selected in the first mode regardless of data held in said holding device, a signal causing said sub-pixel to turn on or off according to the data held in said holding device;

a third switch, adapted to turn on or off according to a scanning signal supplied to a corresponding one of said scanning lines in the second mode, that samples voltage signals supplied to said corresponding second data line; and

a sub-pixel electrode to which a signal selected by said second or third switch is applied.

11. The electro-optical apparatus according to claim 10, further including a storage capacitance that holds a voltage applied to a corresponding sub-pixel electrode.

12. The electro-optical apparatus according to claim 11, said storage capacitance having an end connected to said sub-pixel electrode and also having the other end connected to a potentiostatic signal line.

13. The electro-optical apparatus according to claim 11, capacity of said storage capacitance being determined according to the area of a corresponding sub-pixel electrode.

14. A piece of electronic equipment, comprising:

said electro-optical apparatus according to claim 9.